Coreopsis plant named ‘Polaris’

ABSTRACT

A new cultivar of hybrid  Coreopsis  named ‘Polaris’ that is characterized its compact plant habit reaching 37.5 to 45 cm in height and an average of 37.5 cm in spread, its prolific blooming habit from mid June until frost in Connecticut, its large inflorescences with ray florets that are are solid white in color with no eye zone (even under cool growing conditions), its relatively sterile inflorescences when grown under typical garden conditions that do not require deadheading of spent blooms for continuous bloom, and its reliably perennial habit in U.S.D.A. Zone 5.

Botanical classification: Coreopsis hybrid.

Variety denomination: ‘Polaris’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar ofCoreopsis plant, botanically of hybrid origin and known as Coreopsis‘Polaris’ and will be referred to hereinafter by its cultivar name,‘Polaris’. The new cultivar of Coreopsis is an herbaceous perennialgrown for landscape and container use.

The new Invention arose from an ongoing controlled breeding program inHubbardston, Mass. The objective of the breeding program is to develophybrid cultivars of Coreopsis with unique and superior gardenattributes. In particular, to develop cultivars that are long-lived,sturdy, exhibit a true perennial habit and cold hardy to at leastU.S.D.A. Zone 5 in a wide range of flower colors and plant forms.

The Inventor made a controlled cross in July of 2009 in his test gardenin Hubbardston, Mass. between an unnamed plant from his breedingprogram, ref. no. T 09-1, as the female parent and pollen that waspooled from a variety of unnamed plants from his breeding program as themale parent (all nearly sterile). The exact characteristics of thepollen parent are therefore unknown. ‘Polaris’ was selected in Octoberof 2010 as a single unique plant amongst the resulting seedlings.

Asexual propagation of the new cultivar was first accomplished by stemcuttings under the direction of the Inventor in Kensington, Conn. inOctober of 2010. Asexual propagation by stem cutting has shown that thecharacteristics of the new cultivar are stable and are reproduced trueto type in successive generations.

SUMMARY OF THE INVENTION

The following traits have been repeatedly observed and are determined tobe the characteristics of the new cultivar. These attributes incombination distinguish ‘Polaris’ as a unique cultivar of Coreopsis.

-   -   1. ‘Polaris’ exhibits a compact plant habit reaching 37.5 to 45        cm in height and an average of 37.5 cm in spread.    -   2. ‘Polaris’ exhibits a prolific blooming habit from mid June        until frost in Connecticut.    -   3. ‘Polaris’ exhibits large inflorescences with ray florets that        are are solid white in color with no eye zone (even under cool        growing conditions).    -   4. ‘Polaris’ is relatively sterile when grown under typical        garden conditions and does not require deadheading of spent        blooms for continuous bloom.    -   5. ‘Polaris’ is reliably perennial in U.S.D.A. Zone 5.

The female parent of ‘Polaris’, Ref. No. T 09-1, differs from ‘Polaris’in being highly fertile and produces full seed heads that result in aone month blooming period without deadheading. ‘Polaris’ can be mostclosely compared to Coreopsis cultivars ‘Star Cluster’ (U.S. Plant Pat.No. 23,035) and ‘Snowberry’ (U.S. Plant Pat. No. 18,560). ‘Star Cluster’is similar to ‘Polaris’ in having inflorescences with white ray floretsand in being reletively sterile and disease resistant. ‘Star Cluster’differs from ‘Polaris’ in being taller in height and in havinginflorescences with ray florets that are white in color with a smallpurple eye zone with the ray florets becoming suffused with purple undercool growing conditions. ‘Snowberry’ is similar to ‘Polaris’ in havinginflorescences with whitish colored ray florets. ‘Snowberry’ differsfrom ‘Polaris’ in having inflorescences with ray florets that are lightprimrose yellow in color with a maroon eye and in being less reliablyperennial in U.S.D.A. Zone 5.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying colored photographs illustrate the overall appearanceand distinct characteristics of the new Coreopsis.

The photograph in FIG. 1 was taken in late June of a 10 month-old plantof ‘Polaris’ as grown outdoors in a one gallon container in Kensington,Conn. and shows the plant habit in bloom.

The photograph in FIG. 2 was taken in early September of a 6 month-oldplant of ‘Polaris’ as grown outdoors in a one gallon container inKensington, Conn. and provides a close-up view of the inflorescences.

The colors in the photographs are as close as possible with thephotographic and printing technology utilized. The color values cited inthe detailed botanical description accurately describe the colors of thenew Coreopsis.

DETAILED BOTANICAL DESCRIPTION

The following is a detailed description of the new cultivar as observedfor four years in a test garden in Hubbardston, Mass. with the detailedbotanical data collected from six month-old plants of the new cultivaras grown in one-gallon containers in Kensington, Conn. The phenotype ofthe new cultivar may vary with variations in environmental, climatic,and cultural conditions, as it has not been tested under all possibleenvironmental conditions. The color determination is in accordance withThe 2001 R.H.S. Colour Chart of The Royal Horticultural Society, London,England, except where general color terms of ordinary dictionarysignificance are used.

-   General description:    -   -   Blooming period.—Blooms from mid June until frost in central            Massachusetts.        -   Plant habit.—Herbaceous perennial, clump-forming, compact,            upright leafy flowering stems with inflorescences held above            the foliage.        -   Height and spread.—Reaches 37.5 to 45 cm in height and an            average of 37.5 cm in spread.        -   Cold hardiness.—At least to U.S.D.A Zone 5.        -   Diseases resistance.—More resistance to powdery mildew has            been observed in comparison to Coreopsis grandiflora            cultivars grown under the same conditions.        -   Root description.—Fibrous, fine and well-branched.        -   Propagation.—Terminal stem cuttings and division.        -   Growth rate.—Vigorous but stays compact.-   Stem description:    -   -   Shape.—Tetragonal, solid.        -   Stem color.—144A with mature stems flecked with 165A.        -   Stem size.—Main stem averages 9 cm in length with laterals            an average of 5 cm in length (excluding peduncles), average            of 3 mm in width.        -   Stem surface.—Glabrous when young, ridged and sparsely            covered with translucent hairs up to 1 mm in length when            mature.        -   Branching habit.—Freely branched, typically branched as            opposite laterals at each node, average of 3 branches per            main stem, branch internode about 3.5 cm in length.-   Foliage description:    -   -   Leaf division.—Simple.        -   Leaf margins.—Entire to bifid.        -   Leaf size.—Average of 6.5 cm in length and 3 cm in width            when bifid and an average of 6.5 cm in length and 6 mm in            width when entire.        -   Leaf shape.—Lanceolate.        -   Leaf base.—Cuneate.        -   Leaf apex.—Acute.        -   Leaf venation.—Only midrib is visible, not conspicuous, same            coloration as leaf.        -   Leaf attachment.—Sessile.        -   Leaf arrangement.—Opposite.        -   Leaf surface.—Lower surface smooth and dull, upper surface            slightly glossy and very sparsely covered with short stiff            transluscent hairs to small to measure.        -   Leaf color.—Young and mature; upper surface a blend of 137A            and 139A, lower surface 137C.-   Flower description:    -   -   Inflorescence type.—Campitulum with ray florets surrounding            disk florets in the center, forming a radiant head,            inflorescences are borne on terminals arising from leaf            axils, in loose open clusters.        -   Lastingness of inflorescence.—About one week until            senescence of ray flowers, bracts and disk flowers are            persistent.        -   Fragrance.—Slightly fragrant.        -   Quantity of inflorescences.—Very free flowering, over 200            inflorecenses on a six month-old plant.        -   Inflorescence size.—Average 3 cm in depth and up to 6.3 cm            in diameter with disk portion up to 1.25 cm in diameter.        -   Inflorescence buds.—Average of 1 cm in depth and diameter,            shape is spherical, color is a color between 18A and 11A.        -   Peduncle.—Strong, average of 9 cm in length and 1 mm in            diameter, 144A in color, shiny surface.-   Involucral bracts:    -   -   Bract number.—Two rows of 8.        -   Bract arrangement.—Outer bracts are unfused and held at            about a 45° angle when flower is fully open becoming            horizontal to downward after ray florets drop, inner bracts            overlap and surround receptacle with apical portion            spreading (campanulate-like).        -   Bract size.—Outer bracts about 8 mm in length and 2 mm in            width, inner bracts about 1 cm in length and 5 mm in width.        -   Bract color.—Outer bracts, both surfaces; 144A at the base,            137A at the tips, inner bracts; base is 137A with a blend of            165A, tip is a blend of 154B and 137A.        -   Bract texture.—Outer bracts glabrous on both surfaces, inner            bracts waxy on both surfaces.        -   Bract apex.—Acute.        -   Bract base.—Truncate.        -   Bract shape.—Outer bracts lanceolate, inner bracts broadly            lanceolate.-   Ray florets (sterile):    -   -   Number.—8.        -   Shape.—Obovate, appearance of three longitudinal sections.        -   Size.—Up to 3 cm in length and 1.9 cm in width.        -   Apex.—Three-lobed with 0-4 irregular lobules per lobe.        -   Base.—Broadly cuneate.        -   Margins.—Entire on sides, notched on apex.        -   Aspect.—Held flat, perpendicular to peduncle.        -   Texture.—Glabrous on both surfaces.        -   Color.—Upper and lower surface when opening and when fully            open; NN155A.-   Disk florets (male and female):    -   -   Number.—An average of 80.        -   Shape.—Tubular, corolla is fused, flared at apex.        -   Size.—About 6 mm in length and 2 mm in width.        -   Color.—In masse; 17A, corolla; base (tube) is 9B in color,            flared portion is 17A.        -   Receptacle.—About 8 mm in diameter and 3 mm in depth, N144A            in color.-   Reproductive organs:    -   -   Presence.—Disk flowers are perfect, ray flowers sterile.        -   Gynoecium.—1 Pistil, 5 mm in length, style is very fine and            11C in color, bifid pillose stigma is 16A in color with            branches about 1 mm in length and recurved, ovary is 2 mm in            length, 1 mm in width, placement is inferior, translucent            and 150D in color.        -   Androcoecium.—5 stamens, fused into tube surrounding style,            3 mm in length and 0.7 mm in width, about 166A in color, no            pollen was observed.        -   Fruit.—No fruit development was observed, relatively            sterile.

It is claimed:
 1. A new and distinct cultivar of Coreopsis plant named‘Polaris’ as herein illustrated and described.